Boiler construction



NOV. 2, 1965 OLSEN BOILER CONSTRUCTION 2 Sheets-Sheet 1 Filed July 11,1963 .1 x I l: v l K I. ha .3 n no a n :28 Iit u a a a a 8:5 v u a 1 f vu c c u 233 iwhl W nNHH .3 g 3 o n on 803 .ll v 3 no no a o no 0260ATTUP/VE) Nov. 2, 1965 A. R. OLSEN BOILER CONSTRUCTION 2 Sheets-Sheet 2Filed July 11, 1965 INVENTOR.

A/P/VOZD A? 0A 557V United States Patent 3,215,123 BOILER CONSTRUCTIONArnold R. Olsen, Brooklyn, N.Y., assignor to Thermal RefractoriesCompany, North Bergen, N.J., a corporation of New Jersey Filed July 11,1963, Ser. No. 294,304 2 Claims. (Cl. 122-478) This invention relates toboiler construction and particularly to the steam generating type whichis used in marine environments.

Marine boiler construction is fairly simple, and is comprised of acombustion chamber, in which a selected fuel (oil, powdered coal, etc.)is burned to generate gases in a temperature range typically of from2200 to 2600 F. These gases are caused to flow across upright generatortubes, which extend between a mud or water drum and a steam drum.Usually, these tubes are divided into two groups: a forward group and arearward group, between which are positioned superheater tubes. Thesuperheater tubes are normally held in position at right angles to thegenerator tubes by tube sheets. Tube sheets are relatively thin metalplates suspended within the space between the two sets or groups ofgenerator tubes.

The tube sheets have the distressing propensity to rapidly oxidize inservice, if the hot combustion gases from the combustion chamber areallowed to directly impinge upon them. Various solutions have beensuggested to overcome this difiiculty, such as, for example, welding orotherwise aflixing a plurality of thin sheet metal fins to the generatortubes and superheater tubes adjacent the tube sheet, in order to divertthe flow of combustion gases and prevent direct impingement on the tubesheet. As one might well imagine, whereas the tube sheet may be wellprotected, the fins have a tendency to erode rapidly in service. Anotherdifliculty with the fins is the expense of installation. Further, whenthe fins become extensively eroded, they must be burned off before newones can be substituted.

Refractory castable, with wire mesh reinforcing, has been suggested as ameans of protecting the tube sheets. While removal is easy, the castableand wire reinforcing is rather diflicult to install, particularly in theoverhead or suspended position in which the tube sheet is normallylocated.

Ceramic tile, usually fabricated of silicon-carbide-because of itsthermal and mechanical strength and good thermal conductivity-has beensuggested as a means to deflect the combustion gases from directimpingement on the tube sheets. However, even though various mating andso-called self-locking ceramic tile designs have been suggested, theyhave not been entirely satisfactory, since, in some instances, the tilefall from position during actual operation of the boiler.

Accordingly, it is an object of this invention to provide an improvedboiler construction, which includes means to protect superheater tubesheets from direct impingement with combustion gases. It is anotherobject of the invention to provide superheater tube sheet protectionmeans, which are rapidly and easily installed in conventional marineboilers with a minimum of modification thereof. It is, still further, anobject of the invention to provide means for turbulent deflection of theflow of combustion gases directed against generator tubes andsuperheater tubes in a marine boiler to promote better heat conductingrelation between the gases and tubes, which means is easily installed.

Briefly, according to one aspect of the invention, I provide a pluralityof self-locking pairs of deflector tile. A plurality of these pairs oftile is constructed and arranged to be positioned in stacked relationbetween an adjacent pair of closely spaced, parallel generator tubes.The

lowermost tile of the lowermost pair of self-locking tile has a notchformed in it arranged to loosely substantially entirely encompass or bepositioned over a smaller, but complementary shaped lug welded orotherwise affixed to one of the pair of generator tubes between whichthe tile are stacked. When I say lowermost tile of the lowermost pair ofself-locking tile, I mean to describe that the tile having the notchformed in it and which, when it is itself suspended by the lug, supportsits mate to form a self-locking pair.

Further details of construction, and other objects and advantages ofboiler construction according to this invention, will be readilyapparent to those skilled in the art from the following detaileddescription, with reference to the drawings; in which like referencenumerals are used to designate like parts in the several views. In thesedrawings:

FIG. 1 is a fragmentary perspective view, partially broken away and inpartial section, to better show internal arrangement of parts, of marineboiler construction having the benefits of this invention;

FIG. 2 is a fragmentary side elevation of a portion of the arrangementof FIG. 1;

FIG. 3 is the top elevation of the arrangement of FIG. 2;

FIG. 4 is a fragmentary end detail of the arrangement of FIG. 2;

FIG. 5 is a fragmentary side elevation of the arrangement of FIG. 2; and

FIG. 6 is a fragmentary schematic view of a composite installation usingthe teachings of this invention.

Before describing the drawings in detail, it should be understood theyare but exemplary of practices according to this invention; and theimprovements disclosed and claimed herein should not be considered aslimited to the apparatus embodiment shown in the drawings but, rather,the true spirit and scope of the invention should be as defined in thehereafter appended claims.

Particularly in large marine vessels, it is common to use a steamgenerating boiler as a portion of the power plant thereof. These boilersare most generally of the water tube variety, in which the inner wallsof a combustion chamber are lined with a plurality of tubes; and,further, include banks of tubes of various special constructionsarranged for contact with hot products of combustion, to heat waterpassing through them, to thereby generate steam. The fuel for theseboilers is, conventionally, a pulverized carbonaceous material, such ascoal, or oil. In FIG. 1, I have shown what can be considered anexemplary boiler construction. It includes a main combustion chamber 10.A front wall 11 has a burner port 12 openin g therethrough for theobvious purpose of entering the fuel into the combustion chamber.

A sidewall, rearwall and roof are partially shown in FIG. 1. Thesidewall includes the outer sheet steel skin 15, having a layer ofrefractory castable 16 along the inner surface thereof. Block insulation17 is positioned over the castable 15. Refractory tile 18 face the blockinsulation and are the inner wall of the combustion chamber. The roof issimilarly constructed and includes the outer sheet metal shell or skin20, the inner layer of castable 21, block insulation 22, and the innerface of refractory tile 23. The rearwall, which is faced with refractorytile 24, and the other sidewall, which is not shown in the drawings, areof construction similar to the other walls. The floor of the burnerchamber is comprised of an outer metal skin 25, castable 26, blockinsulation 27, refractory brick 28 and a refractory monolith floor 29.This moonlith floor can be, for example, a sodium silicate bondedpericlase grain.

Within chamber 10, to one side of the burner port 12, are positioned awater drum 30 and a steam drum 31.

The water drum 30 is supported on the floor of the combustion chamber,and the steam drum 31 is shown supported in or by the roof. A pluralityof generator tubes opens between the water tank 30 and steam tank 31.These tubes are, generally, divided into the two groups 32 and 33. Theforward group 32, under stabilized operating conditions, generates steamat a temperature of about 450 F. and at about 600 psi. pressure. Thissteam is passed upwardly through the pool of water 34 in the bottom ofthe steam drum 31. Steam evolving from this body of water 34, is passedthrough a header (not shown) opening from the rear of the steam drum toflow into and through the substantially horizontally disposed banks ofsuperheater tubes 35. These superheater tubes 35 are maintained asbundles, and suspended in position by tube support sheet 36. The steam,after passing through the superheater tubes 35, is on the order of about800 F. (The above temperatures and pressures are, of course, exemplaryand are, generally, indicative of conditions found when the combustiongases are between 2200 and 2600 F., as mentioned above.) The rear groupof generator tubes 33 conduct water downwardly from the pool 34 to thewater drum 30.

The superheated steam from superheater tubes 35 is conducted to aturbine or reciprocal engine installation (not shown) in a known mannerto propel a vessel or the like in Which the boiler is installed. Theparticular type of superheater tubes 35, shown in the drawings, aretermed hairpin tubes in the art.

It is conventional to run tubes through the walls behind the refractoryface tile, but we have not shown them in the drawings to maintainsimplicity herein.

As mentioned above, the tube sheet 36 is normally a plate or sheet ofmetal and is rapidly oxidized when it is subjected to direct impingementby gases exiting from the combustion chamber 10. The water or steamwhich passes through the generator tubes and superheater tubes protectsthem from this rapid oxidation and, thus, the tube support sheet is theweakest point in the tube system. To protect the tube sheet 36 fromdirect impingement, I suspend a plurality of pairs of interlockingdeflector tile 40 in stacked relation to each other. These tile arearranged for mounting between adjacent parallel pairs of forwardgenerator tubes 32. When so mounted, they deflect the gases travelingfrom the combustion chamber and prevent direct impingement thereby onthe tube support sheet 36. More detail of deflector tile constructionand relation with the generator tubes 32 in an installation according tothis invention is most clearly seen by reference to FIGS. 2 through 5.The tile of a self-locking pair of tile 40 are actually two identicaltile, one of which has been inverted so respective biased or slopedsurfaces 41 abut each other. The outer edge or face of each of the tile40 is grooved its entire length to provide an arcuate longitudinaldepression 42, capable of partially encompassing in face to facerelation at least a portion of the outer surface of a generator tube 32.As is seen most clearly in FIG. 2, from the rear, 21 pair of tile show arectangular configuration with a sloped cut through it. This sloped cutis the interface of abutting sloped faces 41. The forward face of eachtile of a pair of tile is outwardly curved, as at 43, to together form asmooth convex surface arranged to deflect impinging gases towards andagainst the generator tubes between which the pair of tile are placed.

Upper and lower surfaces of the tile which make up the pairs of tile arepreferably flat so they may contiguously lie in stacked relation on orbeneath other pairs of tile, as is shown in FIG. 2.

The lowermost tile 40A of a stacked plurality of selflockin-g pairs ofdeflector tile is notched as at 50. The notch 50 is sufficiently largeas to completely cover, in loose relation, a lug 51, which is welded orotherwise affixed to the inner or side face of one of the pair ofgenerator tubes 32 between which a stacked plurality of the self-lockingtile are to be positioned. When I say completely encompass, in referringto the size of the notch 50 relative to the lug 51, I mean it is ofsufiicient depth to prevent direct impingement on a contained lug bycombustion gases traveling towards them. The bottom of the notch is, ofcourse, open; although, it may be closed with a conventional siliconcarbide type mortar, if one so desires. The notch and lug have verticalbisectors lying in a plane common to that of a vertical bisector of thegenerator tube to which the lug is attached.

The foregoing construction, described relative to FIGS. 2 through 5, canbe seen to provide a rapidly and easily installed arrangement forpreventing direct impingement of high temperature combustion gases ofsuch as tube sheet 36. My construction has still other advantages anduses. For example, referring to FIG. 6, I show its use to fabricatesuspended bafiies for convection control. The parts I have shown in FIG.6 are, generally, the same as those shown in FIGS. 1 through 5; but Ihave appended the letter B to similar parts, in order to avoid confusion. For example, the water drum 30B and steam drum 31B have aplurality of generator tubes opening between them, one of which isindicated at 32B in FIG. 6. A plurality of the self-locking tile isshown in position to form two suspended baffles. The first, at 58,includes a plurality of interlocking tile 40B; the lowermost tile 40ABof the series of the interlocking tile 40B is shown to include a notch50B capable of loosely encompassing the lug 51B which is welded to thegenerator tube 32B. Silicon carbide cement is indicated at 52 to sealthe space between the steam drum 31B and the baflie at 58. This baffleconstruction is used to prevent short circuiting of combustion gasesclosely adjacent the steam drum. Lacking such a baffle, the gases,instead of traveling over the mass of tubes which are positioned lower,may tend to rush upwards across the roof and below the steam drum 31B.

A second baffle installation is shown at 53, which bafile installationis comprised, again, of a plurality of self-locking tile 40B, thelowermost of which 40AB includes a notch 50B of sufficient dimension asto encompass a lug 51B. This baflie is supported a distance above thewater drum 30B and, further, assists in inducing turbulentcounterflowing of combustion gases to assure intimate heat conductingcontact between the generator tubes and superheater tubes.

The lug 51B, or the lug 51, is so positioned as to allow insertion of awhole number multiple of a plurality of pairs of the self-locking tileabove the lug and below the steam drum. To do this, one must allow forspace to remain above the stacked plurality of deflector tile. If thisspace is not allowed for, considerable difiiculty will be had when oneattempts to set the last pair of tile above the plurality of previouslypositioned tile and below the steam drum. For example, considering theindividual tile to be on the order of 4" in height, I would suggestleaving about three inches. A pair of tile can then be sawed crosswisein half and inserted and the remaining space filled with a refractorymortar such as silicon carbide mortar, or else the entire space can befilled up with silicon carbide mortar.

As to an exemplary suggested vertical dimension for the composite boilerbaffle, described above, it may run from 10 to about 40% of the totalvertical distance between the water drum 30 and steam drum 31. Theprecise dimensions are, of course, very flexible.

Having thus described the invention in detail and with suflicientparticularity as to enable those skilled in the art to practice it, whatis desired to have protected by Letters Patent is set forth in thefollowing claims.

I claim:

1. The combination with a boiler having a combustion chamber, an uppersteam drum and a lower water drum with a plurality of upright generatortubes running between the steam drum and water drum, and a group ofsuperheater tubes, said generator tubes divided into at least twoupright groups to define a space therebetween transversely Within whichspace is suspended a plurality of superheater tubes, said superheatertubes at least partially supported in position by at least one tubesupport sheet which is transverse of the superheater tubes, said tubesupport sheet being a relatively thin metal plate extending downward ina space between said two upright groups, of a plurality of self-lockingpairs of deflector tile positioned in stacked relation between at leastone adjacent pair of the generator tubes, and means suspending thestacked pairs of selflocking deflector tile between adjacent pair ofgenerator tubes in position to completely cover the edge of said supportsheet normally exposed to the flow of combustion gases to deflect saidcombustion gases from direct impingement on the superheater tube supportsheet, said means suspending the tile comprised of lug means affixed tothe exterior surface of one of the generator tubes and a slot formed inthe lowermost tile of the lowermost pair of self-locking tile, saidnotch encompassing said lug in loose fitting relation and to asuflicient extent to prevent impingement of combustion gases on saidlug.

2. The combination of claim 1 in which the tile are silicon carbidetile.

References Cited by the Examiner UNITED STATES PATENTS OTHER REFERENCESPublication: Refractories, published by General Refractories Co.,Philadelphia, Pa. Copyright, pages 23 to 25.

JAMES W. WESTHAVER, Primary Examiner.

KENNETH W. SPRAGUE, PERCY L. PATRICK,

FREDERICK L. MATTESON, JR., Examiners.

1. THE COMBINATION WITH A BOILER HAVING A COMBUSTION CHAMBER, AN UPPERSTEAM DRUM AND A LOWER WATER DRUM WITH A PLURALITY OF UPRIGHT GENERATORTUBES RUNNING BETWEEN THE STEAM DRUM AND WATER DRUM, AND A GRUP OFSUPERHEATER TUBES, SAID GENERATOR TUBES DIVIDED INTO AT LEAST TWOUPRIGHT GROUPS TO DEFINE A SPACE THEREBETWEN TRANSVERSELY WITHIN WHICHSPACE IS SUSPENDED A PLURALITY OF SUPERHEATER TUBES, SAID SUPERHEATERTUBES AT LEAST PARTIALLY SUPPORTED IN POSITION BY AT LEAST ONE TUBESUPPORT SHEET WHICH IS TRANSVERSE OF THE SUPERHEATER TUBES, SAID TUBESUPPORT SHEET BEING A RELATIVELY THIN METAL PLATE EXTENDING DOWNWARD INA SPACE BETWEEN SAID TWO UPRIGHTGROUPS, OF A PLURALITY OF SELF-LOCKINGPAIRS OF DEFLECTOR TILE POSITIONED IN STACKED RELATION BETWEEN AT LEASTONE ADJACENT PAIR OF THE GENERATOR TUBES, AND MEANS SUSPENDING THESTACKED PAIRS OF SELFLOCKING DEFLECTOR TILE BETWEEN ADJACENT PAIR OFGENERATOR TUBES IN POSITION TO COMPLETELY COVER THE EDGE OF SAID SUPPORTSHEET NORMALLY EXPOSED TO THE FLOW OF COMBUSTION GASES TO DEFLECT SAIDCOMBUSTION GASES FROM DIRECT IMPINGEMENT ON THE SUPERHEATER TUBE SUPPORTSHEET, SAID MEANS SUSPENDING THE TITLE COMPRISED OF LUG MEANS AFFIXED